Transrectal ultrasonic guidance has been used to direct transperineal implantation of radioactive gold seeds (198Au) in 75 patients with localized prostatic carcinoma since January 1984. In 20 patients, follow-up ultrasound scans were available and showed declines of 12 ±6% (mean ± SE) in prostatic volume at 3 months, 40 ± 8% at 6 months, 45 ± 9% at 9 months, and 43 ± 10% at 12 months. There were no significant differences in the amount and rate of prostatic shrinkage according to tumor grade or stage, but shrinkage was significantly greater in patients who received a cumulative dose of 15,000 rads than in those who received 9,000 rads. Three patients had severe symptoms of radiation cystitis, which has necessitated continued anticholinergic drugs in two. One of these three also had a rectal ulcer that healed spontaneously. The rate of residual cancer at present is 40%; we are continuing to rebiopsy at yearly intervals. Our results suggest that transperineal transcutaneous placement of 198Au seeds provides high-dose radiation to the prostate. The histopathologic effects need further long-term study.
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